[Bug]: Translation issues still unresolved

[AinzRimuru]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

I have updated to the latest version, but the language is still not updated to the language of my computer (Simplified Chinese).
The language used by the software is still English after a certain update.

Steps to reproduce

No need to do anything

Expected behavior

Show Chinese

Which files are affected by this bug

None

Operating system

Windows

Which version of the operating system you are running.

Windows11

Package

Official Windows MSI

Nextcloud Server version

30.0.2

Nextcloud Desktop Client version

3.16.2

Is this bug present after an update or on a fresh install?

Updated from a minor version (ex. 3.4.2 to 3.4.4)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

Additional info

[nilsding]

thanks for reporting this issue again!
the one that we resolved with #8081 was affecting macOS only.

in that PR I also added some extra logs at application startup to help with diagnosing issues regarding translations there. --> can you please try a daily build and post the first few log lines? (I'm interested in the ones that contain application.cpp:)

[AinzRimuru]

I installed the daily build.
The version now displayed is: 3.17.0 alpha (Windows).
I don't see the logs containing what you describe.
@nilsding

[nilsding]

@AinzLimuru thanks for providing the logs
I was interested in these two lines (found them in 20250329_2254_nextcloud.log.0.gz):

2025-03-29 22:54:23:142 [ info nextcloud.gui.application C:\Users\User\AppData\Local\Temp\windows-29568\client-building\desktop\src\gui\application.cpp:1006 ]:	System UI languages are: QList("zh-Hans-CN", "zh-CN", "zh", "en-US", "en-Latn-US", "en")
2025-03-29 22:54:23:142 [ info nextcloud.gui.application C:\Users\User\AppData\Local\Temp\windows-29568\client-building\desktop\src\gui\application.cpp:1009 ]:	selected application language: "zh_Hans_CN"

seems like we need to update the language substitution function used during application startup... I'll see what I can do

[AinzRimuru]

Thank you for your efforts.
@nilsding